In hospitals and other places there may be a great deal of equipment and case records which are constantly being relocated. A lot of time is wasted in finding the equipment. It is therefore expedient to have a flexible system that can determine the position of various units.
In areas where there is electronic equipment that is sensitive to electromagnetic radiation, it is inadvisable to introduce new equipment that generates such radiation, such as a transceiver based on radio waves. The measurements of the new equipment in turn will be influenced by the existing equipment.
Systems based on ultrasound will be suitable, since they will not be affected by electromagnetic radiation and will have little effect on the environment.
A weakness of known systems based on ultrasound is that the results of the measurements will be influenced by noise sources such as fluorescent tubes and computer screens. This will detract from the quality of the received signals. Another shortcoming of known systems is that they will not work when the chip transmitting the signals is in motion.
An object of the invention is to reduce the influence of noise sources to a minimum.
A second object is to perform position determination even though the chip whose position has to be determined is in motion.